Fix CFI macro definitions in aarch64 assembly for Linux

The CFI macros were expanding to themselves instead of actual .cfi_* directives,
causing assembly errors on Linux. Fixed to expand to proper directives.

Author: kristjanvalur

stackman/platforms/switch_aarch64_gcc.S

@@ -29,11 +29,11 @@
 #define TYPE_FUNCTION(name) .type name, %function
 #define SIZE_FUNCTION(name) .size name, .-name
 #define GNU_STACK .section .note.GNU-stack,"",@progbits
-#define CFI_STARTPROC CFI_STARTPROC
-#define CFI_ENDPROC CFI_ENDPROC
-#define CFI_DEF_CFA_OFFSET(x) CFI_DEF_CFA_OFFSET()x
+#define CFI_STARTPROC .cfi_startproc
+#define CFI_ENDPROC .cfi_endproc
+#define CFI_DEF_CFA_OFFSET(x) .cfi_def_cfa_offset x
 #define CFI_OFFSET(r,o) .cfi_offset r, o
-#define CFI_RESTORE(r) CFI_RESTORE()r
+#define CFI_RESTORE(r) .cfi_restore r
 #endif
 
 	.arch armv8-a